Because of adverse effects associated with the administration of whole cell vaccine, development of improved pertussis vaccines is of high priority. The Food and Drug Administration is responsible for ensuring that these vaccines are both safe and effective. We have therefore developed a battery of assays to test the safety and potency of these vaccines. These assays test the vaccines for purity, lack of toxicity, lack of the ability to revert to a toxic form, and immunogenicity. In particular, efforts have been expended to develop a potency assay for acellular pertussis vaccine which can be used as a reliable measure of the reproducibility of manufacture of these vaccines. A standardized ELISA is currently being developed which will measure the immune response in mice to the four antigens found in acellular pertussis vaccines. These antigens are filamentous hemagglultinin, pertussis toxoid, 69 kDa protein, and fimbriae.